Claudia Hammond presents a series looking at the development of the science of psychology during the 20th century. She re-visits Ellen Langer and Judith Rodin's 1976 study, conducted in a New England nursing home, Arden House. When the two psychologists set up the experiment so that residents on two floors of the 360-bed home for the elderly would experience some changes in their everyday life, they had no idea that they were introducing factors which could prolong life. While residents on both floors were given plants and film shows, only those on the fourth floor had the opportunity to control these events: choosing the plant and looking after it themselves, and choosing which night of the week to view the film. Eighteen months later, when Langer and Rodin returned to the home, they were astonished to discover that twice as many of the elderly residents in this 'choices' group were alive, compared with the control group on the second floor, who had been given plants that the staff tended, and were told which was their film night. It appeared that taking control made you live longer. These findings fit in well with the work on learned helplessness in dogs which Martin Seligman had done in the late 1960s, and on Langer and Rodin's own studies on the perception of control. Claudia Hammond meets Ellen Langer, now Professor of Psychology at Harvard, and hears about Arden House and the work she has gone on to do on what she calls 'mindfulness'. She visits Arden House, which is still a nursing home, and is shown around by current administrator Joanne Scafati. Dr Zelda Di Blasi, who lectures in psychology at University College, Cork, sets the study in context, and Rosalie Kane, Professor of Public Health at the University of Minnesota, and Howard Kaplan, CEO of City Club Living accommodation for the elderly, discuss the impact of Langer/Rodin on care of the elderly.